Rotary jet bit for jet drilling and cleaning

ABSTRACT

A jet bit ensures precise drilling of holes through the earth&#39;s surface, such as drainholes around a well. The jet bit has front rotating orifices and jets to drill a hole in a medium larger than the diameter of the bit. The orifices directed to the rear provide thrust to propel the bit forward by enlarging the drainhole. A stationary shroud extends beyond the front orifices to maintain the front jets rotation. The jet bit may include turbine to control rotation rate and torque on front jets containing rotating shafts. A jet bit can be small enough to turn in a radius of four (4) inches from a vertical wellbore to create a horizontal drainhole. Various mechanical cutters can be mounted on the front of the jet bit to enable cutting with both jets and mechanical cutters.

This application claims priority of provisional application No.61/743,025 filed on Aug. 24, 2012.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention describes a jet bit for drilling drainholes in the earthand can be used for cleaning tubulars and other materials. One versioncontains a turbine for controlling rate of rotation of front jets andtorque to rotate the shaft connected to the front orifices. One versioncan be turned in a short radius of four inches from vertical tohorizontal for drilling drainholes in oil/gas reservoirs.

2. Description of Related Art

Jet bits (Jet bits) and background for drilling drainholes are describedin U.S. Pat. No. 4,790,394 (Dickinson et. al.); U.S. Pat. No. 5,853,056(Landers); U.S. Pat. No. 6,206,112(Dickinson); U.S. Pat. No. 6,263,984(Buckman); and U.S. Pat. No. 6,668,948 (Buckman).

Currently no other jet bits exist that have rotating front jet bits thatwhen connected to high pressure hose will turn in a radius of fourinches or less from vertical to horizontal to drill horizontaldrainholes. It is obvious that the Badger is too large and without ashield to keep the spinning jet bit away for the formation, the frictionbetween the front of the jet bit and formation will cause the front tocease to rotate.

What is needed is a jet bit that can be turned in a radius of less thanfour inches when connected to a high pressure hose. It needs to have astandoff to enable it to drill a hole through an oil/gas formationwithout the front of the jet bit ceasing to turn because of frictionbetween it and the formation. It needs to drill drainholes through theearth having diameters large enough for the jet bit to pass through andlarge enough to allow the cuttings to pass outside the jet bit and thetubular to which the jet bit is attached. It needs to cut hard and softreservoirs more efficiently and economically than current jet bits inuse. The bit should also have thrust force so that it has its own motiveforce from rear thrusters.

BRIEF SUMMARY OF THE INVENTION

A rotary jet bit is provided that contains a turbine that controls thetoque and rate of rotation of front jets and can be turned in a radiusof less than four inches from vertical to horizontal to drill drainholesin oil/gas reservoirs. It is designed such that the rotating front jetshave a standoff so that the front of the rotating bit will continue toturn and will not come into contact with the formation so that the frontjets will continue to turn to continue jet drilling to producedrainholes in the formation and/or removing solid material solidmaterials from tubulars and other enclosures. The rotary jet bitcomprises a non-rotating outer body consisting of inlet housing and abearing housing connected to a high pressure fluid source; a rotatinginner shaft in the outer body that is connected to and rotates a drillhead that has orifices. It has a turbine consisting of an inlet of oneor more stationary stator blades connected to the outer body and one ormore rotating rotor blades attached to the rotating shaft that rotatesthe shaft connected to a high pressure drill head; a dynamic sealbetween the outer housing and the rotating shaft to prevent leakage ofhigh pressure fluid past the rotating shaft to the exterior of the jetbit; and a bearing assembly in the bearing housing to transfer hydraulicand mechanical axial loads on the rotating shaft to the non-rotatingstationary outer body; thus providing rotating straight jets on front ofthe drill head to provide more capable and efficient jet drilling thanjet bits currently in use that use stationary straight jets or swirlingfull cone fluid jets.

DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and theadvantages thereof, reference is now made to the following descriptiontaken in conjunction with the accompanying drawings in which thereference numbers indicate like features and wherein:

FIG. 1 a illustrates a complete rotary jet turbine powered jet bit.

FIG. 1 b Drawing of a rotary jet turbine powered jet bit with rearorifices.

FIG. 2 A rotating shaft and drill head with front orifices.

FIG. 3 Illustrates fluid flow through stationary turbine vanes thrustingonto rotating turbine vanes to produce torque to rotate shaft.

FIG. 4 Illustrates fluid seal and fluid flow from high pressure tooutside.

FIG. 5 a Jet bit containing bearings, high pressure fluid passage, andtorque created by jets from angled front orifices to turn drill head.

FIG. 5 b Jet bit with angled jets on front to produce torque to turncutter head and containing rear jets for propulsion.

FIG. 6 Dissolvable cap to keep debris from entering nozzle and to enablejet bit to go by sharp transitions.

FIG. 7 Jet bit containing mechanical cutters on the front.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 a contains the elements of a rotary jet bit whereas a rotatingshaft 12 turns inside an outer housing 10 with rotating shaft attachedto cutting head with orifices 24 to enable the rotating front orificesto effectively drill and clean solid material. The jet bit has an inlethigh pressure fluid connection 8 with an inlet housing 10 a bearinghousing 14 containing bearings 20 to enable the rotating shaft 12 toturn relative to bearing housing 14. At the front of inlet housing 10 isa turbine 30 with stationary angled vanes to conduct the high pressurefluid into vanes into the rotating turbine to produce rotation of therotating shaft 12. This high pressure fluid passes through the turbineand through the hollow part of the cutting head and through cutting headorifices 24 that are rotating with the cutter head. The seal 22 servesto reduce the leakage of fluid from the rotating shaft 12 to the outsidethrough bearing exhaust 26; bearing exhaust 26 also reduces pressure onthe bearings. Seal 22 can be a labyrinth seal, O-rings, metal seal(example; beryllium copper) and other configurations to contain the highpressure in the conducting channels from the inlet 8, through theturbine vanes and to the orifices 24. This rotary jet bit can be made ofvery small dimensions with total diameter of less than ½ inch and alength of less than one inch and sizes up to three inches in diameterwith lengths greater than eight inches. FIG. 1 b has added to theelements of FIG. 1 a the rear orifices 28 that create high pressure jetsto propel the jet bit forward and also cuts the material the jet bit isdrilling to produce larger effective bores and to also improve theremoval of cuttings from the drainholes. FIG. 2 illustrates thegeometrical relation of the rotating shall 12 to the Cutting Head 18 andillustrates that they are integrally connected and turn at the samerate.

FIG. 3 illustrates that fluid flowing through the stationary inlet vanesof the turbine 30 impinges onto the rotating vanes 32 to produce arotation of the rotating shaft 18. By sizing these vanes and changingtheir angles and using different flow rates the rate of rotation of therotating shaft 12 can be varied from very slow rotation, less than 10revolutions per minute, to more than 10,000 revolutions per minute. Theturbine vanes enable significant torque to power the jet bit turn evenwith significant frictional forces in the jet bit and/or debris in frontof the jet bit. Seal 22 is a labyrinth rotating seal as illustrated inFIG. 4 that seals the high pressure fluid inside the jet bit from thelow pressure fluid in the outside of the jet bit. This pressuredifferential is equal to the pressure drop across the orifices. Thepressure drop across the labyrinth seal is created as a small amount offluid leaks through a series of restrictions in the seal in turbulentflow. This fluid leakage flow passes through bearings 20 and cools andlubricates them. The bearing assembly 20 in the bearing housing 14transfers the hydraulic and mechanical axial loads on the rotating shaft12 to the non-rotating stationary outer body. A cylindrical shroud 16attached to the bearing housing typically extends beyond the front ofthe cutting head 18 such that the material being cut does not negativelyinfluence the rotation of the cutting head 18. Advantages of the turbinepowered jet bit are that the turbine is highly reliable, it can provideconsiderable torque and power to the rotating shaft and cutter head, andthe rotary speed and torque of the turbine can be varied by the designof the turbine vanes, and by varying the flow rate and the pressuredifferential across the turbine.

FIG. 4 illustrates the flow of liquid through the seals with a smallamount flowing on the outside to of the bearings.

FIG. 5 a consists of an embodiment that has the same elements as the jetrotary turbine powered jet bits in FIG. 1 b with the turbine vanesremoved. In this rotary jet bit the torque produced on the cutting head18 and the rotating shaft 12 is by the reaction of the torque generatedby the fluid through the orifices located on the cutter head 18. Therear jets due to orifices 28 will provide thrust to propel the jet bitforward and the high pressure jets will also cut the material to make alarger equivalent drainhole. FIG. 5 a has the same elements as FIG. 5 bwithout the rear orifices 26. In this case the jet bit is attached to atubular and pushed forward by the tubular force at connection inlet 8.

FIG. 6 consist of a protector cap 34 that is placed on the jet bit toprotect the head from debris and allow clearance through sharptransitions. The protector cap 34 is a water soluble material thatdissolves away and does not to disrupt cutting operations.

FIG. 7 is similar to FIG. 5 b with the addition of mechanical cutters 40also on front of the jet bit to enable the bit to cut both with highpressure jets and also mechanical cutters such as polycrystallinediamond (PDC), tungsten carbide, silicon carbide, or silicon nitride.

DESCRIPTION OF PREFERRED EMBODIMENT

Let us now consider one preferred embodiment of the turbo jet drill usedto jet drill drainholes in wells in the earth. The Parts 10, 12, 14, 16,18, 30 and 32 are constructed using stainless steel. The total diameterof the jet bit is nominally ½ inch and the length is about 1.2 inches.The jet bit is designed to withstand pressures of 15,000 psi or more andthe front bit and turbine are designed to turn at a rate of 200 rpm orgreater with a thrust force from the rear jets of 10 lbs. to more than50 pounds.

We claim:
 1. A jet bit for jet drilling, comprising: a non-rotatingouter body consisting of inlet housing and a bearing housing connectedto a high pressure fluid source; a rotating inner shaft in the outerbody that is connected to and rotates a drill head; a drill head hasorifices that under high pressure fluid are angled to produce torque toturn the drill head and to produce high pressure fluid jets to drillsolid materials; a turbine consisting of one or more stationary statorblades attached to the outer body and one or more rotating rotor bladesattached to the rotating shaft to rotate the shaft and the high pressuredrill head; a dynamic seal on the rotating shaft to prevent leakage ofhigh pressure fluid past the rotating shaft to the exterior of the jetbit and reducing flow through the drill head; a bearing assembly in thebearing housing to transfer hydraulic and mechanical axial loads on therotating shaft to the non-rotating stationary outer body. The jet bit ofclaim 1 where the fluid pressure drop across the orifices is between 500and 40,000 pounds per square inch.
 1. The jet bit of claim 1 including aturbine consisting of one or more stationary stator blades attached tothe outer body and one or more rotating rotor blades attached to therotating shaft to rotate the shaft and the high pressure drill head. 2.The jet bit of claim 1 where the inlet housing and bearing housing arecombined into one housing.
 3. The jet bit of claim 1 where rear directedorifices in the non-rotating outer body produce jets that produce aforward force on the drill head as it drills.
 4. The jet bit of claim 4where rear directed jets cut slots in the in the rock surrounding thejet drilled holes to increase flow of oil and gas from oil and gasbearing formations.
 5. The jet bit of claim 1 where one or more sidedirected jets in the drill head are used to increase the diameter of thejet drilled hole.
 6. The jet bit of claim 1 where angled jet bits areused in the drill head to provide torque to rotate the shaft and drillhead instead of turbine blades.
 7. The jet bit of claim 1 where aMoineau motor is used to rotate the shaft and high pressure drill head.8. The jet bit of claim 1 where the bearing assembly is a ball or rollerbearing.
 9. The jet bit of claim 1 where the bearing assembly is ahard-metal sliding bearing that utilizes polycrystalline diamond,ceramic or other hard-metal sliding surfaces.
 10. The jet bit of claim 1where the bearing assembly is a journal bearing.
 11. The jet bit ofclaim 1 where the dynamic seal is a labyrinth seal.
 12. The jet bit ofclaim 1 where the dynamic seal is an o-ring seal.
 13. The jet bit ofclaim 1 where the dynamic seal is a metal to metal seal.
 14. The jet bitof claim 1 where the dynamic seal is a deformable material seal.
 15. Thejet bit of claim 1 where the dynamic seal is a face seal.
 16. The jetbit of claim 1 where the dynamic seal is a lip seal.
 17. The jet bit ofclaim 1 where the dynamic seal is a packing seal.
 18. The jet bit ofclaim 1 where the dynamic seal is a nested V or a nested conical seal.19. The jet bit of claim 1 where the dynamic seal is a mechanical seal.20. The jet bit of claim 1 where the dynamic seal is a balanced orunbalanced seals.
 21. The jet bit of claim 1 where a screen is placed inthe jet bit to prevent small particles from plugging the high pressureorifices.
 22. The jet bit of claim 1 where hard-metal mechanical cutterssuch a polycrystalline diamond (PDC), tungsten carbide, silicon carbideand silicon nitride cutters are applied to the drill head to assist thehigh pressure jets in drilling hard materials.
 23. The jet bit of claim1 where the drill head is contained in a shroud to protect it frommechanical damage or plugging by debris from the material being drilled.24. The jet bit of claim 1 where the assembly is pushed forwardmechanically by a tube or other means instead of by rear jets.
 25. Thejet bit of claim 1 where a diverter is used in an existing well to turnthe jet rotating head so that it will drill inclined or horizontallateral wells from existing wellbores.
 26. The jet bit of claim 1 wherea flexible tube or hose is used behind the rotating drill head to allowpassage through the curved passageway in the diverter.
 27. The jet bitof claim 1 where the outer body of the jet drilling assembly is flexibleso that that the assembly can pass around shorter radii turns indiverters.
 28. The jet bit of claim 1 where a hydraulic or electricmotor is used in an existing well to rotate a flexible shaft that passesthrough a diverter and rotate the jet drilling assembly to drillinclined or horizontal lateral wells from existing wellbores.
 29. Thejet bit of claim 1 where the jet bit is used to remove cement, scale,paraffin and other materials from inside oilfield drillpipe, oil and gasproduction tubing, oilfield casing and from tubulars in geothermal,water, and disposal wells.
 30. The jet bit of claim 1 where the jet bitis used clean the inside of industrial tubing such as heat exchangertubes.
 31. The jet bit of claim 1 where the jet bit is used to cleanproducts in non-drilling applications.
 32. The jet bit of claim 4 wherethe jet bit rear jets and front jets are both used for cleaning.
 33. Thejet bit of 1 where it uses a water soluble protector cap to allowclearance through sharp transitions and protects from debris.